I think the familial dynamics as they relate to MBTI are fascinating.
Father: IXTX (ISTJ?)
Mother: INFP
Brother: IXFX (ISFP?)
Sister: INFP
Me: INTP
My dad is an IXTX (ISTJ?). My dad divorced my mom when I was about three, so I live with my mom. Luckily I was young enough that I hadn't really developed an attachment to my dad. I don't really think of him as a dad. He's more like an uncle to me. I don't know him that well primarily for two reasons. First of all, I only see him about once per year. Secondly, he masks his true personality with what he thinks is the socially acceptable personality. I think he's very insecure, but doesn't know how to deal with it. I know he's a good person, whoever he is. He just needs to be himself.
My mom is an easy INFP. She screams FP especially. Not a very logical type. Often rejects my use of logical arguments (as per her inferior Te) because she often does not understand them. We often have deep discussions about a number of things. She'll let me explain some sort of cool idea even if she can't quite grasp it (especially when it pertains to mathematics or science). We get into a lot of arguments. Usually the same ones over and over. My T and her F do not get along. She's accepted my independence and, for the most part, treats me as a friend rather than a son, which I appreciate greatly.
My older brother is an IXFX (ISFP?). He was diagnosed with a rather severe form of agenesis of the corpus callosum (ACC) at birth, and is thus difficult to type. He has a childlike demeanor, so it's really not possible to tell if he is S or N, as most kids don't show a lot of N until their teens. He's always the happiest guy in the house and his unfaltering enthusiasm can make a bad day a good one. He is sometimes very social, but is definitely drained by prolonged socialization and he'll then get very quiet and antisocial, refusing to talk to anyone.
My sister is an INFP. She and my mom get along great. My sister and I get along well, often engaging in curious discussions. She has a better grasp on logic than my mom. We tend to have the same views on most issues. Like me, she has many J qualities, but is definitely P.
I am an INTP. I'm 75% I, 95% N, 70% T, and 55% P (though I think my T is actually higher). I don't do drugs, or get into trouble, but I am definitely the odd-one-out in the family. My logical reasoning is usually disregarded, so I make a good scapegoat. I was generally a very disobedient child. As an INTP, I cannot tolerate unfairness. I had long thought that I was doing the wrong thing by disobeying her, but I mostly only disobeyed her when she wanted me to do or not do something for illogical reasons. I think, looking back, it was for the best, though I cannot be sure.
